Functional Mesoporous Hybrids

Organonitrile-functionalized mesoporous silicas such as MCM-41 and MCM-48 have been used to immobilize dioxoMo(VI) complexes such as Mo02X2(THF)2 (with X = Br or Cl) (218). The catalytic potential of these hybrid material was evaluated for the epoxidation of cyclooctene with r-BuOOH as the oxygen source. Notwithstanding the high activities claimed, pronounced Mo leakage was observed. Indeed, it was shown that cyclooctene continued to be converted after the solid catalyst was removed from the reaction mixture (218). 

Palaniappan A, Li X, Tay FEH, Li J, Su X (2006) Cyclodextrin functionalized mesoporous sflica films on quartz crystal microbalance for enhanced gas sensing. Sens Actuators B Chem 119 220-226 Palaniappan A, Moochhala S, Tay FEH, Su X, Phua NCL (2008) Phthalocyanine/silica hybrid films on QCM for enhanced nitric oxide sensing. Sens Actuators B Chem 129 184—187 Pejcic B, Eadington P, Ross A (2007) Environmental monitoring of hydrocarbons a chemical sensor perspective. Environ Sci Technol 41(18) 6333-6342... 

Vila, N., Ghanbaja, J., Aubert, E., and Walcarius, A. (2014) Electrochemically assisted generation of highly ordered azide-functionalized mesoporous silica for oriented hybrid films. Angew. Chem., Int Ed., 53 (11), 2945 2950. 

FIGURE 1. Supramolecular objects consist of inorganic building blocks mainly based on soft supramolecular assemblies, (a) Hybrid lipid thin films, (b) Layer-by-layer assemblies, (c) Structure transcription, (d) Functional mesoporous hybrid. 

In this volume we have collected 10 review chapters from distinguished scientists who have contributed extensively to the study and development of supramolecular assemblies that contain metals and metal-like elements with unusual structures and morphologies and possess potentially useful (and applicable) physical and biological properties. The first chapter by K. Ariga et al. is a general discussion of supramolecular structures that contain inorganic building blocks for hybrid lipid thin films, layer-by-layer assemblies, structure transcription, and functional mesoporous hybrids. This is followed by two chapters, the first by M. L. Kistler et al., who describe the self-assembly of hydrophilic polyoxometalate (POM) macro-anions and examine the structure and behavior of POM macro-ions in solution. This is followed by a chapter by S. K. Das, who provides an overview of the supramolecular features of POM-supported transition metal complexes, POM-crown ether complexes with supramolecular cations, and supramolecular water clusters associated with POMs. 

Mishra, A.K., KuUa, T., Kim, D.Y., Kim, N.H., Lee, J.H., Protic ionic liquid-functionalized mesoporous sihca-based hybrid membranes for proton exchange membrane fuel cells, J. Mater. Chem., 2012, 22, 24366-24372. 

In addition, one of the main areas in PMO is organically functionalized PMO (hybrid periodic mesoporous organosilica (HPMO)) [43, 44] (Figure 3.3). Organically functionalized PMO is currently an area of intensive research because of its unique properties and potential applications. 

Second, amine moiety-functionalized mesoporous materials have been also synthesized by co-condensation under various reaction conditions for uniform distribution of organic groups and to prevent Si-C cleavage upon template removal. Many researches have shown that co-condensation is one of the most successful pathways to hybrid materials with uniform distribution of the organic moiety. The reaction pathway with a template such as a polyethylene oxide-based amphiphile under acidic conditions is used. This pathway provides not only hexagonal but also cubic structures. 

Mann and coworkers proposed a unique method to prepare nanohybrids of mesoporous silica and gold nanoparticles mediated by programmed DNA hybridization, as illustrated in Figure 4.21 [186], MCM-41 nanoparticles were first functionalized with a 3 -amino-terminated 12-base single strand oligonucleotide... 

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